What Are The Types Of Refractories For Ladles?

Steel ladle is also called steel drum is an important container of metallurgical industry, plays the role of storage, transit steel, but also to carry out the dual task of refining outside the furnace, with the development of steelmaking technology, China's steel ladle refractory materials have also been well developed. With the development of steelmaking technology, China's ladle refractories have also been well developed. The length of service life of the ladle is not only related to the consumption of refractory materials, but also directly affects the normal production of steelmaking. Especially with the improvement of the life of the converter, the increase of continuous casting ratio and the progress of refining technology outside the furnace, ladle is in a large capacity, more steel, high temperature, long time and other increasingly harsh conditions of use, the requirements for refractory materials for the ladle are also increasing, so the world are actively researching and developing a variety of new materials refractory material, in order to improve the quality of existing refractory materials, to extend the service life of refractory materials, reduce the tonnage consumption of refractory materials. Refractories tonnage consumption.

In our country generally its nominal capacity of 50 tons in the following converter without refining ordinary ladle, its work lining is generally used casting material overall casting molding. The one-time service life of the working lining is generally about 50-60 times, and the highest is about 70-80 times, even more than 100 times in individual steel mills. In order to reduce the consumption of tons of steel refractory, many steel mills ladle lining in the use of a certain number of times, the residual lining surface of the residual steel, residue cleaned off, commonly known as peeling, and then sit on the mold pouring a certain thickness of pouring material, to be baked to continue to be put into use, which can greatly reduce the cost, the process is also known as set of pouring, and its first left behind by the remnants of the lining is equivalent to the permanent lining, to maintain the service of the package for 2-3 times. The materials of ladle working lining are aluminum-magnesium, high alumina spinel, etc. According to the binding agent, it can be divided into low cement, ultra-low cement and cementless refractory castables.

1,High-alumina spinel castables

Since the ladle lining indefinite refractory materials since the 80's since the popularization and application, has been from the original ordinary aluminum and magnesium castables to the development of aluminum and magnesium spinel castables, castables performance improved significantly. Aluminum-magnesium spinel castables have the advantages of high density, high strength, erosion resistance, spalling resistance, low wear rate, etc., which can significantly improve the age of the package, and thus are adopted by many manufacturers. Lining process from pounding, projecting, vibration development to mold vibration, mold vibration reduces ladle refractory consumption. Good results have been achieved, and the average ladle age can reach 70-80 times. It has the advantages of even vibration, easy operation, high labor efficiency, and can realize continuous pouring of ladle lining.

2.Low Cement Refractory Castables

Low-cement refractory castables are developed on the basis of clay-bonded refractory castables, and they are a new generation of refractory castables that have been vigorously developed in the 1980s. Its main varieties are low cement, ultra-low cement and cementless refractory castables, which combine the advantages of many kinds of refractory castables, featuring high density, low porosity, high strength, low abrasion, heat shock and erosion resistance, etc., as well as strong volumetric stability and low water consumption for construction, etc. Therefore, it is widely used, and has a better effect of use and significant socio-economic benefits.

Clay brick

Clay brick is China's earliest use of ladle refractory materials, the 20th century, 50 ~ 60 years, China's ladle refractory materials are mainly used in a variety of clay bricks, due to the use of low-cost, until the 80s there are still a number of steel mills ladle is still used in the use of clay bricks. A steel mill ladle with clay brick physical and chemical indicators are: Al2O3 44.10%, SiO2 52.10%, Fe2O3 1.72%, the apparent porosity of 16% ~ 18%, room temperature compressive strength of 54.9 ~ 96.0 MPa. Clay ladle lining brick service life due to the use of different steel mills in different conditions. Although now China's ladle has no longer use clay bricks, but clay bricks to China's early recovery of the steelmaking industry and later development has made a significant contribution.

High aluminum brick

With the continuous development of steelmaking technology and steel production and quality continues to improve, clay ladle lining brick due to the use of short life, since the end of the 1960s, some of China's steel mills ladle began to use a variety of high-alumina lining bricks, so that the life of the ladle has increased dramatically.

Wuhan Iron and Steel flat furnace with 270t ladle from 1968 began to use second-class high alumina bricks, to 1970 the age of the package reached 25.7 times, is the clay lining brick 2.5 times. 1974 the age of the package reached 31.5 times. Wuhan Iron and Steel two steelmaking converter with 70t ladle from 1980 to use Al2O3 content greater than 72% of high alumina bricks, the age of 34 times, up to 50 times.

Baosteel 300t ladle from June 1986, the whole package wall using a refractory materials factory production of first-class high alumina bricks, the average age of about 50 times. After the continuous casting machine put into operation, the ladle use conditions deteriorate, the service life of the bag lining is shortened. Baosteel and some refractory production enterprise cooperation, developed the use of excellent performance micro-expansion of high alumina bricks, in April 1992 the official use of A factory products, the average service life of 81.5 times, the highest life expectancy of 100 times. The average service life of the products of B factory is 78.6 times, the highest reached 122 times (continuous casting ratio of 55.73%).

TISCO 70t ladle using high aluminum lining brick, service life of 64.3 times.

In short, China's ladle after the use of high aluminum lining brick, so that the service life of the ladle significantly improved to ensure the smooth progress of steel production, and promote the further development of the steel industry.

Wax tiles

Wax stone brick is a kind of sintered products produced by foliated wax stone as the main raw material.In the early 1970s, a refractory factory in Fujian produced wax stone ladle bricks in Maanshan Iron and Steel, Anshan Iron and Steel, Shanghai Iron and Steel three factories, Sanming Iron and Steel and other iron and steel enterprises in different types of ladle on trial. The results show that the use of wax stone brick performance is better than the use of clay bricks and third-class high alumina bricks. Used on 15t ladle of Masteel, the life span reached 66 times. Wuhan Iron and Steel two steelmaking plant 70t ladle also tried the production of the plant's SiO2 content of 72% of the wax stone brick, but the effect is not very satisfactory, the service life of only 14 times. Baosteel 300t ladle in September 1985 to 1988 years have been used in Japan imported wax brick, the average life expectancy of 38 times. The physical and chemical indexes of wax stone brick for ladle produced by a factory are as follows: SiO2 78.95%, Al2O3 18.85%～19.51%, Fe2O3 0.44%～0.52%, apparent porosity 14%～18%, normal temperature compressive strength 32.9～62.9MPa. Due to various reasons, wax stone brick has not been popularized and applied to the ladle in our country.

Aluminum and magnesium unburnable bricks

In addition to aluminum and magnesium pounding material, aluminum and magnesium castables, our country also developed a combination of water-glass aluminum and magnesium non-burning bricks, in the ladle on the use of life than the traditional alumino-silicate ladle bricks long. Bensteel 160t ladle using aluminum and magnesium unburnable bricks, the average life of 40.56 times, than the use of three high alumina bricks (life of 18.5 times) to improve more than 1 times. Tianjin three steelmaking plant 20t ladle using aluminum and magnesium unburnable brick average life 38.8 times, up to 55 times, is clay lining brick life (9 times) more than 4 times.

Aluminum-magnesium-carbon bricks

In the 1990s, is the rapid development of China's continuous casting technology period, high-efficiency continuous casting technology has become the center of gravity of its development. In order to improve the service life of continuous casting ladle, to adapt to the needs of the development of high-efficiency continuous casting technology, our country has developed a ladle with aluminum magnesium carbon bricks for various types of continuous casting ladle, so that the service life of the ladle greatly improved. Luonai hospital, baosteel and jiaozuo a refractory materials factory co-developed aluminum magnesium carbon ladle bricks in baosteel 300t continuous casting ladle on the use of ladle age from the use of first-class high alumina bricks more than 20 times, increased to more than 80 times, the highest reached 126 times. Anshan Iron and Steel three steelmaking 200t all continuous casting and furnace refining ladle, the use of aluminum-magnesium carbon bricks, the average life expectancy of 64 times, up to 73 times. 1993 ladle with high-quality aluminum-magnesium carbon bricks with the popularization of the use of the full-scale in our country, many of the country's steel mills, according to the actual situation of the enterprise, one after another, the use of aluminum-magnesium carbon ladle lining bricks, so that the ladle's life expectancy significantly increased, such as Pangangang 160t ladle using aluminum-magnesium carbon lining bricks, the average life expectancy increased to 90 times, the average life expectancy of 60 times. After using aluminum-magnesium-carbon lining bricks, the average lifespan of the ladle has increased to 90 times, with a maximum of 115 times. Aluminum-magnesium-carbon bricks are made of special high-alumina bauxite clinker, electrofused magnesium sand or sintered magnesium sand and graphite as raw materials, and liquid phenolic resin as binding agent.

High-grade aluminum and magnesium unburnable bricks

Carbon-containing ladle lining brick in the use of the process will cause the molten steel carbonization, smelting clean steel, low carbon steel and ultra-low carbon steel is very unfavorable. In order to meet the needs of clean steel, low carbon steel and ultra-low carbon steel smelting, the development of high-grade aluminum and magnesium non-burning bricks (carbonless non-burning bricks). High-grade aluminum and magnesium non-fired brick and the early 1980s development of water-glass combination of aluminum and magnesium non-fired brick compared to a qualitative leap. In addition to the use of high-purity raw materials (corundum, high-purity fused magnesium sand and high-purity aluminum and magnesium spinel, etc.), the combination of agents are also used in high-performance composite binding agent. High-grade aluminum and magnesium non-burning bricks in the ladle on the use of good results, the service life to reach or even exceed the carbon ladle lining bricks, while reducing the carbon increase in molten steel. Such as Henan a refractory materials company developed aluminum and magnesium not burning brick, in a steel plant 100t ladle and LF refining ladle on the use of life is aluminum and magnesium carbon brick 1.5 times. Anshan steel 200t ladle using aluminum-magnesium non-burning brick once the age of the package in more than 110 times, up to 128 times. 170t continuous casting ladle service life reached 119 times, more than the aluminum-magnesium carbon brick. Baosteel 300t continuous casting ladle from June 1998 to stop using aluminum and magnesium carbon bricks, began to use high-grade aluminum and magnesium unburnable bricks.

Magnesium-carbon brick

Magnesia carbon bricks have excellent erosion resistance and spalling resistance. Magnesium carbon brick in the ladle is mainly used in the slag line parts, while the non-slag line parts use other refractories (castables, unburnable bricks, etc.), which can obtain a higher service life, but also reduce the cost of refractory materials. A steel mill ladle slag line with magnesium carbon brick physicochemical indicators: MgO77.4%, C16.75%, apparent porosity 3.1%, bulk density 2.903g/cm, room temperature compressive strength of 38.6MPa. 1981 September WISCO two steel mills took the lead in the 70t ladle slag line using magnesium carbon brick, service life of 50 times, due to non-slag line parts of the high alumina brick damage is serious and out of service. Baosteel 300t ladle slag line from July 1989 began to use MT-14A magnesium carbon bricks, slag line life is maintained at more than 100 times. A steel mill 90tLF refining ladle slag line using carbon content of about 16% of the magnesium-carbon bricks, slag line life of 95 times. There are also steel mills ladle with full magnesium-carbon brick lining, such as a steel plant with 60tLF-VD electric furnace refining ladle, full magnesium-carbon brick lining, the average life of 47 times, up to 57 times.

Low carbon magnesium carbon bricks

Steel ladle slag line using magnesium carbon bricks exist in the steel carbon problem, in recent years, some steel mills and refractory manufacturers to cooperate, the development of a low carbon steel ladle slag line magnesium carbon bricks. Baosteel 300t ladle slag line tried carbon content of less than 7% and less than 5% of the low-carbon magnesium-carbon bricks, the service life of up to 110 times or so, and ordinary magnesium-carbon bricks comparable to basically meet the requirements of the use of 300t ladle. Anshan steel ladle slag line also used in the carbon content of 5% or less of the low-carbon package lining brick, the use of good results.

Unburnt magnesium-calcium bricks

At the beginning of 1990s, Lonai Academy developed the non-burning magnesium-calcium bricks for ladle with synthetic magnesium-calcium sand and electrofused magnesium sand as raw materials, and solid inorganic salt and inorganic salt solution as combining agent, and used them on 40tLF-VD refining ladle of a steel plant in Shanghai, with the life span of more than 40 times, and the oxygen content of the steel decreased from 12.2×10-6 to 11.13×10-6. In 1992, the product passed the appraisal of the former Ministry of Metallurgy, and then was used on the refining ladle of Great Wall Special Steel and other steel plants. In 1992, the product passed the appraisal of the former Ministry of Metallurgy, and then it was used in the refining ladle of Great Wall Special Steel Plant and other steel mills. In recent years, a refractory company developed anhydrous resin-bonded non-burning magnesium-calcium bricks, which were used in a steel company's 100tLF refining ladle, with a life span of 80-85 times and an erosion rate of 1.28-1.37mm/times. In July-August 2006, Shandong Magnesium Mining cooperated with a refractory factory to develop non-burning magnesium-calcium bricks, which were used in a steel factory's 90tLF refining ladle (refining rate 100%) package wall non-slag line part of the use, life expectancy of more than 60 times. Because of the bottom of the package air permeability brick serious erosion and discontinued, not burned magnesium calcium brick thickness of about 130mm, can continue to use, is expected to normal package age up to 80 ~ 100 times.

Unburned magnesium-calcium-carbon bricks

At the beginning of this century, Shougang two steelmaking plant and a refractory materials company, with synthetic magnesium and calcium sand, electrofused magnesium sand and high-purity graphite as raw materials, anhydrous resin as a bonding agent, developed a non-burning magnesium-calcium-carbon bricks, used in Shougang two steelmaking plant, 225t ladle non-slag line parts (slag line magnesium-carbon bricks), the average service life of 116.8 times, and the original use of aluminum-magnesium-carbon bricks compared to the case of the packet wall is thinned by 20mm, the average life increased by 37.57 times. Compared with the original aluminum-magnesium-carbon bricks, the average service life is 116.8 times. And the oxygen content in the steel and non-metallic inclusions have been reduced. There are also some steel mills in SKF and LF-VD and other refining ladle slag line parts of the use of magnesium calcium carbon brick, achieved good results.

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